Forum: Nitro Useful parts

What would be the most useful generic parts, aside from the admin part,
to have in a 0.50 distribution?

The admin part is an essential component, but there are others that
would serve both as examples and as useful building blocks to speed
anyone's first project with Nitro.

Candidates, to my mind, would be

Parts:

 - User management, possible a homologue to Rails' RBAC ( Role Based
Access Control )
 - Wiki and Blog components
 - Arne's Flickr thingy

Elements:

 - Tag cloud
 - Breadcrumb trail

Others?